PODEROSO Juan Jose
capítulos de libros
Effects of oxidative burst inhibitors on nitric oxide production in human neutrophils- Biochemistry
CARRERAS MC, RIOBÓ N, DEL BOSCO CG, PODEROSO JJ,
The Biology of Nitric Oxide, Part. 5.
Año: 1996; p. 89 - 89
Human neutrophils (PMN) generate nitric oxide (NO) simultaneously with superoxide anion with formation of peroxynitrite in the presence of activators of NADOH oxidase like formyl peptides (fMLP). There are no reports about possible effects of burst inhibitors on NO synthase pathway. The purpose of this study was to compare NO and hydrogen peroxide (H2O2) production of fMLP-stimulated PMN in the presence of agonists of inhibitory receptor signals, adenosine (A) and isoproterenol (ISO) and modulators of G proteins activity like Cholera (CT) and Pertussis (PT) toxins. Hydrogen peroxide was measured by a fluorescence assay and NO by the oxymyoglobin assay or electrochemically in PMN stimulated with 1 µM fMLP. Preincubation with A or ISO, decreased H2O2 generation in a dose-dependent manner up to 80% and 100% of control values, respectively, while NO production was only decreased 50% in the presence of A but it was not affected by ISO. A different sensitivity to both toxins was also observed; CT inhibited the H2O2 and NO production by 100% and 56% while PT decreased them 90% and 14%, respectively. The marked PT inhibition of H2O2 release allowed to detect NO electrochemically. The results suggest that, in human PMN, both inhibitory or activating pathways of signal transduction to NO synthase are different from those of NADPH oxidase and that, changes in the respective pathways modify, in accordance, the final peroxynitrite levels.